Healthcare Response to Weapons of Mass Destruction: Biological, Chemical and Radiological

Chemical Terrorism

Chemical agents used as weapons are likely to be detected more quickly in the population than are biological agents, because an incubation period is not needed. Chemical agents can have very serious health effects, some are immediate and other effects take time to be felt. Many chemicals are not easily detected, so that a likely scenario is that a large number of people will become sickened before the chemical attack is identified. Epidemiologic clues that might suggest the covert release of a chemical agent include (CDC, 2003d):

  • An unusual increase in the number of patients seeking care for potential chemical-release--related illness;
  • Unexplained deaths among young or healthy persons;
  • Emission of unexplained odors by patients;
  • Clusters of illness in persons who have common characteristics, such as drinking water from the same source;
  • Rapid onset of symptoms after an exposure to a potentially contaminated medium (e.g., paresthesias and vomiting within minutes of eating a meal);
  • Unexplained death of plants, fish, or animals (domestic or wild); and
  • A syndrome (i.e., a constellation of clinical signs and symptoms in patients) suggesting a disease associated commonly with a known chemical exposure (e.g., neurologic signs or pinpoint pupils in eyes of patients with a gastroenteritis-like syndrome or acidosis in patients with altered mental status).

However, it is also possible that a covert release of a chemical agent might not be identified easily for a number of reasons (CDC, 2003d):

  • Symptoms of exposure to some chemical agents (e.g., ricin) might be similar to those of common diseases (e.g., gastroenteritis);
  • Immediate symptoms of certain chemical exposures might be nonexistent or mild despite the risk for long-term effects (e.g., neurocognitive impairment from dimethyl mercury, teratogenicity from isotretinoin, or cancer from aflatoxin);
  • Exposure to contaminated food, water, or consumer products might result in reports of illness to healthcare providers over a long period and in various locations;
  • Persons exposed to two or more agents might have symptoms not suggestive of any one chemical agent (i.e., a mixed clinical presentation); and
  • Healthcare providers might be less familiar with clinical presentations suggesting exposure to chemical agents than they are with illnesses that are treated frequently.

As with the planning for a biological attack, healthcare organizations also have planned for the possibility of a chemical attack. Each professional is urged to identify and read the emergency response plan for chemical attacks in her/his healthcare organization. These plans have been made in response to state and federal requirements. While specifics will vary from organization to organization, the overall goals will be similar.

In the event of a chemical release, public health officials, defense and emergency personnel would be directing the population as to how to proceed. The Agency for Toxic Substance Disease Registry (ATSDR), in 2001 released Managing Hazardous Materials Incidents: A Planning Guide for the Management of Contaminated Patients, Vol. I-III. It provides information about how to manage such emergencies, including the prehospital and emergency department management. Prehospital guidelines describe the activities that typically occur in the three concentric areas surrounding the hazardous materials (HAZMAT) incident. This would apply to any intentional or accidental release of chemicals.

  • The Hot Zone (or Exclusion Area) is the area surrounding the chemical release; it is assumed to pose an immediate health risk.
  • The Decontamination Zone (or Warm Zone) is the area surrounding the Hot Zone where primary contamination is not expected but where personnel must use protective clothing and equipment to avoid chemical exposure from contaminated victims.
  • The Support Zone (or Cold Zone) is the outermost ring where no exposure or risk is expected. The incident commander, medical personnel, and other support persons and equipment operate in the Support Zone.

According to ATSDR (2001) guidelines, rescuers should be trained and appropriately attired before entering the Hot Zone. If the proper equipment is not available, or if rescuers have not been trained in its use, call for assistance from a local or regional HAZMAT team or other properly equipped response organization.

When a chemical is unidentified, worst-case possibilities concerning toxicity must be assumed. The potential for severe local effects (e.g., irritation and burning) and severe systemic effects (e.g., organ damage) should be assumed when specific rescuer-protection equipment is selected.

  • Respiratory Protection: Pressure-demand, self-contained breathing apparatus (SCBA) should be used in all response situations.
  • Skin Protection: Chemical-protective clothing should be worn when local and systemic effects are unknown.

Quickly ensure a patent airway. If trauma is suspected, maintain cervical immobilization manually and apply a cervical collar and a backboard when feasible.

If victims can walk, lead them out of the Hot Zone to the Decontamination Zone. Victims who are unable to walk may be removed on backboards or gurneys; if these are not available, carefully carry or drag victims to safety.

In the Decontamination Zone, whenever the chemical or concentration is unidentified, personnel should wear the same protective equipment used in the Hot Zone (see above).

Quickly ensure a patent airway. Stabilize the cervical spine with a collar and a backboard if trauma is suspected. Administer supplemental oxygen as required. Assist ventilation with a bag- valve-mask device if necessary. Victims who are able and cooperative may assist with their own decontamination. Remove and double-bag contaminated clothing and personal belongings.

Flush exposed or irritated skin and hair with plain water for 3 to 5 minutes. For oily or otherwise adherent chemicals, use mild soap on the skin and hair.

Flush exposed or irritated eyes with plain water or saline for at least 5 minutes. Remove contact lenses if present and easily removable without additional trauma to the eye. If a corrosive material is suspected or if pain or injury is evident, continue irrigation while transferring the victim to the Support Zone, for further treatment or to be transported to a hospital.

In cases of ingestion, do not induce emesis. Victims who are conscious and able to swallow should be given 4 to 8 ounces of water. Obtain medical care immediately.

In the Support Zone, be certain that victims have been decontaminated properly (see Decontamination Zone above). Victims who have undergone decontamination or who have been exposed only to gas or vapor and who have no evidence of skin or eye irritation generally pose no serious risks of secondary contamination. In such cases, Support Zone personnel require no specialized protective gear.

Quickly ensure a patent airway. If trauma is suspected, maintain cervical immobilization manually and apply a cervical collar and a backboard when feasible. Ensure adequate respiration; administer supplemental oxygen as required. Ensure a palpable pulse. Establish intravenous access if necessary. Attach a cardiac monitor.

Intubate the trachea in cases of respiratory compromise. When the patient's condition precludes endotracheal intubation, perform cricothyroidotomy if equipped and trained to do so.

Treat patients who have bronchospasm with aerosolized bronchodilators. Use these and all catecholamines with caution because of the enhanced risk of cardiac dysrhythmias after exposure to certain chemicals. Patients who are comatose, hypotensive, or have seizures or cardiac dysrhythmias should be treated according to advanced life support (ALS) protocols.

Facilitate transport to a medical facility. Report to the base station and the receiving medical facility the condition of the patient, treatment given, and estimated time of arrival at the medical facility.

If a chemical has been ingested, prepare the ambulance in case the victim vomits toxic material. Have ready several towels and open plastic bags to quickly clean up and isolate vomitus.

In an ideal situation the decontamination process would occur in the field, near the site of exposure, prior to reaching the hospital. According to OSHA Best Practices for Hospital-Based First Receivers of Victims (2005), worst-case scenarios take into account challenges associated with communication, resources, and victims. During mass casualty emergencies, hospitals can anticipate little or no warning before victims begin arriving. Additionally, first receivers can anticipate that information regarding the hazardous agent(s) would not be available immediately. Hospitals also can anticipate a large number of self-referred victims (as many as 80 percent of the total number of victims) and assume victims will not have been decontaminated prior to arriving at the hospital (OSHA, 2005).

Healthcare workers risk occupational exposures to chemical, biological, or radiological materials when a hospital receives contaminated patients, particularly during mass casualty incidents. These hospital employees, who may be termed first receivers, work at a site remote from the location where the hazardous substance release occurred. This means that their exposures are limited to the substances transported to the hospital on victims' skin, hair, clothing, or personal effects. The location and limited source of contaminant distinguishes first receivers from other first responders (e.g., firefighters, law enforcement, and EMS personnel), who typically respond to the incident site (i.e., the Release Zone) (OSHA, 2005).

OSHA guidelines (2005) suggest that hospitals identify:

  • Decontamination Zone which includes any areas where the type and quantity of hazardous substance is unknown and where contaminated victims, contaminated equipment, or contaminated waste may be present. Employees in this zone might have exposure to contaminated victims, their belongings, equipment, or waste. This zone includes, but is not limited to, places where initial triage and/or medical stabilization of possibly contaminated victims occur, pre-decontamination waiting (staging) areas for victims, the actual decontamination area, and the post-decontamination victim inspection area. This area will typically end at the ED door.
  • Post-Decontamination Zone is an area considered uncontaminated. Equipment and personnel are not expected to become contaminated in this area. At a hospital receiving contaminated victims, the Hospital Post-decontamination Zone includes the ED (unless contaminated).

Other agencies such as the Agency for Toxic Substances and Disease Registry (ATSDR) (2001) further divide these zones into more specific functional areas, such as triage, decontamination, and critical care areas, for example.

OSHA (2005) guidelines cover protection for first receivers during releases of chemicals, radiological particles, and biological agents (overt releases) that produce victims who may need decontamination prior to administration of medical care. Although intended for mass casualty incidents as they affect emergency department personnel at fixed hospitals, the basic principles and concepts of this guidance also apply to mobile casualty care facilities and temporary shelters, such as would be necessary in the event of a catastrophic incident involving tens or hundreds of thousands of victims.

Healthcare providers are again reminded to identify and read the emergency plans at their own healthcare organizations.

Continue on to Chemical Terrorism, Con't.